atoi

字符串转int

char a[N];
cin >> a;
int b = atoi(char a); 

push_heap()

建堆，默认原数组已经是个堆，再插入一个元素

int a[N];
for (int i = 1; i <= n; i ++ )
{
    scanf("%d", &h[i]);
    push_heap(h + 1, h + i + 1, greater<int>());    //小根堆
    push_heap(h + 1, h + i + 1, less<int>());   //大根堆
}

make_heap()

建堆，将整个数组调整为一个堆

vector<int> q;  //
for (int i = 0; i < 10; i++) {
    q.push_back(i);
}
make_heap(q.begin(), q.end(),less<int>());

其他heap函数：
https://www.cnblogs.com/woxiaosade/p/10628388.html